<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    /* 实现原理
    1.首先要两个盒子
    2.根据三角形的原理让两个三小型合并来实现
     */
    /* 清除内外边距让它合并 */
    * {
        padding: 0;
        margin: 0;
    }

    div {
        width: 0;
        height: 0;
        border-left: 100px solid transparent;
        border-right: 100px solid transparent;
        border-bottom: 50px solid red;
    }

    p {
        height: 0;
        width: 0;
        border-top: 150px solid red;
        border-left: 100px solid transparent;
        border-right: 100px solid transparent;
    }
</style>

<body>
    <div></div>
    <p></p>
</body>

</html>